Republican, Democrat primaries today

Poll worker Frances Keathley checks a Columbus resident’s ID at Columbus High School at the start of the state primary elections being held today. Today’s Republican and Democratic primaries are the first to be held since Mississippi enacted a voter ID law that requires a photo. Polls are open until 7 p.m. Photo by: Mary Alice Weeks/Dispatch Staff

The election marks the first test of the state's voter ID law. People will be required to show a driver's license or other form of government-issued photo identification at the polls.

In the Republican Senate race, six-term incumbent Thad Cochran is supported by Mississippi's GOP establishment. His major challenge comes from tea party-backed state Sen. Chris McDaniel. A third Republican candidate in the race, Thomas Carey, has spent little on his campaign.

Former U.S. Rep. Travis Childers is one of four candidates in the Democrat Senate primary. Another is Bill Marcy, who has twice run unsuccessfully for the U.S. House as a tea party Republican.

Three congressmen have primary opponents. The only incumbent without a primary is Republican Rep. Alan Nunnelee in north Mississippi's 1st District.

In south Mississippi's 4th District, Republican Rep. Steven Palazzo faces four primary challengers, including the man he unseated in 2010, former Democrat Gene Taylor, who switched parties to run.

Runoffs, if needed, will be June 24.

The Republican Senate primary appears to be a tight race that will depend on whose supporters are more motivated to vote Tuesday, said political scientist Marty Wiseman, retired director of Mississippi State University's Stennis Institute of Government. Mississippi has a history of keeping U.S. senators in office for decades, and 1942 was the last time voters turned an incumbent senator out of office.

Cochran, 76, was elected to the Senate in 1978 after six years in the House. He is a former Senate Appropriations Committee chairman who reminds voters that he has delivered billions of federal dollars to one of the poorest states in the nation, for Hurricane Katrina recovery, university research, military bases and agriculture projects. Top Mississippi Republicans, including Gov. Phil Bryant and U.S. Rep. Gregg Harper, campaigned for Cochran on Monday.

McDaniel, 41, was elected to the state Senate in 2007 and is receiving significant financial backing from Club for Growth and other tea party-friendly groups. Former Alaska Gov. Sarah Palin and former Pennsylvania Sen. Rick Santorum have campaigned for McDaniel in Mississippi in the past week.

"One thing that Palin and Santorum have done is given some additional momentum to Chris McDaniel," Wiseman said Monday. "Right now, you've got to say that McDaniel's base is the most enthusiastic."

The Mississippi Senate race took a bizarre turn in mid-May when four McDaniel supporters were charged in what police called a conspiracy to photograph Cochran's wife on Easter Sunday in the nursing home where she has lived for the past 13 years with dementia. Rose Cochran's image was used in an anti-Cochran video that was posted briefly online April 26.

Police in Madison said the four men conspired to use the images to advance allegations Cochran was having an inappropriate relationship, which the senator denies. McDaniel and others have raised questions about Cochran bringing a female Senate aide on numerous official trips overseas. Cochran's adult children say he remains devoted to his wife. McDaniel says he had no part in the photography incident, calling it reprehensible.